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From DOC through DPF to SCR, Wolf’s ABC of filtration

Throughout the automotive history there has been a wide variety of efforts to reduce the impact of exhaust gas on health and environment. In this article we follow the exhaust gas through three components of the exhaust after-treatment system and we explain how their functionality is influenced by engine oils.

Technical Expertise

Experts in filtration: DOC and DPF

The DOC, or Diesel Oxidation Catalyst, is a catalytic converter focused on reducing the emission of harmful CO and hydrocarbons. The DOC uses a honeycomb structure to maximize the area of contact between the exhaust gas and the catalyst metals which enable the hydrocarbons and CO to break down into CO2 and H2O. The DOC is a smart investment that brings your car a step closer to cleaner mobility; you can see and smell its impact on your exhaust gas.

The DPF, or Diesel Particulate Filter is just like the DOC a real specialist. It collects and burns particles contained in the exhaust gas. The oxidation process takes place in a honeycomb structure, similar to the DOC’s structure. It uses the heat generated by the engine and the DOC to burn the collected particles. But be careful, a clogged DPF filter will mitigate the gained advantages. The DPF can be seen as a son of the DOC. It needs to be protected from too much hydrocarbons which can clog the filter and it uses the DOC’s heat to burn the particles, what an innovative teamwork.

NOx reduction

SCR, or Selective Catalytic Reduction is a catalyst focused on removing the NOx from the exhaust gas. To accomplish this it makes use of one of three additional fluids: urea, anhydrous ammonia or aqueous ammonia. The exhaust gas and catalytic fluid enters the system and pass through a structure containing catalytic metals. They stimulate the transformation from NOx into a variety of less harmful substances controlled by the urea.

Importance of engine oil

The exhaust after-treatment system is not directly attached to the engine oil circulation. This means that no engine oil will flow through one of the system’s components. But don’t underestimate the importance of choosing a lubricant compatible with your after-treatment system.

Every time a combusting takes place a very tiny amount of engine oil gets burned along with the fuel. The residue of the burned lubricant passes through the after-treatment system where it can affect the catalysts or clog one of the filters.

By investing in innovative technologies Wolf is capable of presenting a wide range of products compatible with exhaust after-treatment systems. Any product complying with the ACEA C1-C4 and E6/E9 category will guarantee an all-round protection to compatible diesel engines and exhaust after-treatment systems. The upcoming expansion towards the ACEA C5 specification will widen this innovative product range.

Finding the right engine oil for your vehicle is getting more complex. But Wolf is here to assist you. Wolf’s product finder is a tool that guides you through the process of finding the most optimal engine oil for your vehicle within seconds. With just the brand and type of your diesel vehicle you can find out which engine oil will protect your exhaust after-treatment system whilst maintaining engine protection.

Engine oils

All of these exhaust after-treatment systems are pushing our engines towards a cleaner future but all of them are very vulnerable. This is why choosing the right lubricant for your car is of utmost importance. A little bit of engine oil gets burned during the running of the engine, meaning that the residue of the burned up engine oil passes through the three after treatment systems. Some of these residues can clog the filter or prevent the catalytic fluids or metals from functioning as intended. Mainly the engine oils containing sulphated ash are not compatible with vehicles containing these filters. This is why ACEA, or the European Automobile manufacturers Association, included this differentiation in their lubrication standards. The C1 to C4 and the E6 and E9 are engine oils suited for cars equipped with an after-treatment system. The latest addition to the family is the C5 standard. The progressive and innovative products in the C5 category offer an all-round protection of the exhaust after-treatment systems and an even higher fuel economy. Wolf Oil’s experts always looking for the products and technologies of tomorrow, keep your eyes peeled for the upcoming product releases!

Finding the right engine oil with all this data, traps and abbreviations seems a tedious task. That is why Wolf designed a tool for you to find the right engine oil for your car, including the protection of the after-treatment system! This means that with a few clicks you can find out which oil fits your engine and protects your after-treatment system. As a manufacturer of engine oil we find it our duty to help any customer to find the right lubricant suited for their needs with respect for the environment. Towards a greener future and smarter mobility.

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